Time comparator



April 22, 1952 w. o. BENNETT, JR

TVIME COMPARATOR 7 Sheets-Sheet 1 Filed July 15, 1944 INVENTOR. WILLIAM O. BENNETT, JR.

ATTY.

April 22, 1952 w. o. BENNETT, JR 2,593,650

TIME COMPARATOR Filed July 15, 1944 V 7 Sheets-Sheet 2 INVENTORI WILLIAM O. BENNETT, JR.

ATTY.

April 22, 1952 w. o. BENNETT, JR

TIME COMPARATOR Filed July 15, 1944 7 Sheets-Sheet 3 R J MT! MT .EE m E B O M M L H. W

ATTY.

A ril 22, 1952 w. o. BENNETT, JR 0 TIME coMPARATbR Filed July 15, 1944 '7 Sheets-Sheet 4 FIG 4.

I N VEN TOR.

WILLIAM 0. BENNETT, JR.

ATTY.

W. O. BENNETT, JR

April 22, 1952- TIME COMPARATOR 7 Sheets-Sheet 5 Filed July 15, 1944 d MT T N EE W e E O M M L L W April 22, 1952 w. o. BENNETT, JR

TIME COMPARATOR 7 Sheets-Sheet 6 Filed July 15, 1944 FIG.

INVENTOR- WILLIAM 0. BENNETT, JR.

ATTY.

April 22, 1952 Filed July 15, 1

CITY LINE A O 7 Sheets-Sheet 7 STANDARD 60 CYCLE AC MICROPHONE MAIN /sw|TcH' A 7 6| OPERATING RELAY H STARTING BUTTON AMPLIFYING TE 64/ as 62 63 UNIT TICK SELECTOR SPEAKER ATT Y.

Patented Apr. 22, 1952 TIME COMPARATOR William Ogle Bennett, .rngianca'ster', Pi, is

signer to Hamilton Watch. Company, Lancaster, Pa.

Application July 15, 1944, Serial N0.'5 45-,159

w i u -61 L The present invention is directed to an apparatus by means of which timepieces may be compared with the correct time and the deviation from the correct time indicated.

The purpose of the invention is ,to provide an apparatus hereinafter called a time comparator to permit an operator to determine the variation Q of the dial indication of a timepiece to be tested from standard time.

The object of the present invention isto provide an apparatus for comparing the indicated time of a timepiece with the indicated time of a master timepiece. i

A further object of the present invention is to provide an apparatus which may be operatedby one person to determine the difierence between the indicated time of a timepiece and'thecorrect standard time. I 1 .4

A further object of thepresent inventionis to provide an apparatus with meanstoindicatdto the'hundredth of a second, the difierence, be-

tween the indicated time of a timepiece and the indicated time of a master timepiece.

A further object of the presentinvention is to provide an apparatus having visual means for indicating the beginning and end of asecond.

A further object of the present invention is to provide a time comparator having means for signaling the start and finish of each half second.

A further object of the present invention is to provide an electric clock to be used as a master timepiece, and means for varying the indicated time ofsaid electric clock by measured amounts.

A further object of the present invention is ,to provide an electric clock to serve as a master timepiece, and means for varying the indicated time of said electric clock to coincide with the indicated time of a timepiece to be tested.

A further obiect'ofthe present invention is to provide an electric clock to serve as a master timepiece, and means for varying the indicated time of said electric clock to coincide with 'the indicated time of a timepiece to be tested, and

means for making such coincidence known."

A further obiect of the present invention is to provide an electric clock having means for indicating the start and finish of each. individual second and to provide meansfor varying the start and finish of each individual second to coincide with the start and finish of the corresponding second on the timepiece to be tested together with means for indicating the amount of such variation.

A still further object of the present invention is to provide a time comparator adapted to opcrate on standard frequency and means for setting said time comparator on standard time, a

scale-which may beset a-t zero position with the time-comparator on standard time, means for bringing the-time of-the comparator into coincidence with that of-atimepiece to be tested, said scale-tolindicatethe'timeierror of the timepiece.

still further object-oi the present-invention is .to provide a time comparator with means for indicating time, means for varying the indicated time of -said time comparator, means forsynchronizing said time comparator with standard time and means. for indicating coincidence of said. time omparator- .withithe indicated; timeof atimepiece to-betested.

A still further object of the present invention is to provide a comparator-for marinechronomraters-wherein the comparator is used in combination with' a microphoiieior amplifying the half second ticks of a marine chronometer.

.A still further object of the present invention is to provide a comparator for marine chronometers wherein the comparatoris used in combination with a microphone for amplifying the half seconds ticks of a marine chronometer and means foreliminating alternateQticks.

A still further objectof the present, invention is to pro'videa comparatorfor marine chronometers together with an indicating system for indicating coincidence between a chronometer to be tested and theftime comparator and also for indicating whether said time comparator is either slightly advanced or. retarded with respect to said marine chronometer -fl A still further object of the present invention is to provide an. electric clock mounted .on a rotatable disc and an indicating scale frictionally driven by 'saiddisc andimeans for locking said scalein fixed position.

. A still further object of the present invention is to'provide ashiftab1e zero point by means of which a slight error in the setting .of' the comparator to correct time may be corrected.

A still further object of the present invention is to provide a spiralscale having more than one convolution and a vertically shifting viewing window throughwhich only the desired portion o'ff'lthe, scale maybe seen..

A still further object of the present invention is to provide a safety device by means of which the device is rendered inoperative in event of momentary interruption of the standard power supply.

Fig. 2 is a front plan view of the same.

a sence mounted on a disc 2 and journalediinbearings 3 and d. The disc 2 is carried on a flange E3 .in-

tegral with sleeve 5 which houses a central shaft shaving opinion E thereon. Pinion I engages gear a dr'ivingshaft :liland its attachedhand i i which "indicates seconds orl dial 5-2. An indicat-v in -dial 22 is mounted coaxiallywvith-disc 2,ion *s'leeve'j23wvhich'journais'sleeve 5 and is 1.1'otatab1y supportedin bearing 'i A'dial'recording themev- 'oluticns of 'disc' 2 2 'isdriven from piriion .8'through gear l'- i,' gear,.i'5, gear i5 "and shaft Fig-thus keeping "an accm'a'te count of "the number I of revolu- 'tio'ns "oi-dialed.

"The indicatingdial "22 is keyed'a't 23 to'sleeve '23 *and =carries ii'iction pads 25 which are urged into contact with disc 2 by 'threeprongedspring 25. This friction contact issuchthat-the indica ing -scale 22 moves simultaneously disc 2 under I ordinary "conditions.

' npringmeznbers E6 and-2izengagingdiscii2'providea-clamp wh g h is operated by sci w :28 to hold dial 22 stationerywhile disc 2 is turned or to release "dial 22 to permit ZZ to'b'e'turned simultaneouslywith'disc 2 through the friction-a1 contact of th'e pads 2 Carried on and turning with the shaft "6 is a-can fi. Qontactimechanisms 3635i and-532cm 1 arranged about the'cam'fifi-ccntactingSaid cam and operate :thereby. This'cam *2 9 is preferably so proportioned that two consecutive teeth pass a giverrpoint every second.

The 'con'tact mechanisms 3d, iii and '32 are compose-def a fixed contact and a :movable contact the toothed points of the ream .29

engaging the movable "contact "thus closing an electricaljieircuit between them-cvabie contact Zia-and fixed contact -33. These contact mechanisms-371,3! and 5E arose-spaced about'the cam d9 thatthe'contact 3 l is'contacted first, the contact-3 3 is-contactedsecondly, and the contact 32 is contacted thirdly the-passage oi "the wheel 29 through an arc -ccual 'tokthe-distance between anytwo toothedjpoints. Thisarrangeznent makes it'possible 'to iridica'te 'throught esecontact mechanisms'the' exaetins'tant 'at which'the comparator is synchronized with thechrcnom'eter as'will be eiplained'laterwith reference .to Fig.7. V

The router i iii-operated through contact collecting rings 35 and 33 which receive ourrentirom contacts .3"? and 38 connected to a source of standard-frequency 83*(Fig. 7')

"With regard to the operation of the mocha vnism shownin Figs. 1, 2 and 7.,microphone .39 is placedfin contact with a chronometer 40 .so as to be energized each one-half second. The seconds hand of a chronometer advances twice,lnormally producing two audible ticks every second.

inorder to properly synchronize the seconds hand of the time comparator with the seconds hand of the chronometer to be tested it is imperative that the synchronization takes place at the chronometer across its scale indication.

:former 42 Lto Ia-speaker 43. amplifier consists of two D. C. pulses persecond.

.2" through the pivot '56. 'nism operated through a push button -44 brings the exact instant the hand passes the scale indication. In the apparatus about to be described the electrical impulses, Which are produced as a result of the audible ticks of the chronomet-er are used to indicate this coincidence between the time comparator and the second :hand of the 'chronometer. Itis, therefore, desirable that alternate half second ticks be eliminated and the half second ticks which remain used as an in- .dication'of the passage of the seconds'hand of In the mechanism shown diagrammatically in Fig. '7 theelectrical impulses coming from the secondary of the transformer 32 are. first passed through-.arotating commutator which eliminates one of these electrical impulses. The electrical line is-further carried to a selector mechanism by means of which either the half second period of --electricalcontactfbetween the rotating commutatorand acontact is selected or by changing the 'selectedzcontacts,'thaother-half second period is selected, thus making-it possible to use theelecitricaliimpulses generated-bythe twoaudible ticks of thechronometer, one of which must be produced :as the 'gtim'epiece seconds hand crosses the 'scaleindications.

The microphone is connected to amplifier 4|, the output of which-is passed-through a trans- The output of the Taken from the secondary of theoutput trans- ..formerAEaand-the coil of thespeaker Z-S a line 5 2 is conne'cte'd to a pivot 56 and a line 43' is connected to -.a contact 1-2 respectively. This allows the pulses originated by the audible ticks of the chronometer to be impressed-on'the commutatorfifi which is turned bye. 1 R. P. S. motor The commutator 68 is formed with'a contact section 68 and .an equally extensive insulated section 69. Spring contacts Hi and 1! bearing against the-circumferential portion of the commutator fifi are alternately in circuit with line 43' by reason of contact with sections 68 and 69.

This alternativelycompletes a circuit between 43' "and lines 5'9 and bfl which are selectively-brought into contact with?! and 'S Bcarried on the arm :Whic'hcomp'letes the circuit-between 43 and The selector mechainto -operatioma relay coil 53 which swings the arm 48 about its pivot against the action of spring 49 -advancing the ratchet Wheel 54 which turns the shaft-4=7 and cam 46. Cam 46 swings the arm 55 about the pivot '56 "to bring contacts 57 or 58 .intoielcctric'al contact with'lines5'9'or 6-0 respectively, "thus completing a selective circuit by means of which one of the one-half :second ticks of the chronorneter'is selected. This combination ofithe'insulatedcommutator and ratchet relay completes a contact of oneeha'lf second duration in the circuit .43 and 42' once every second.

The actuating iel'ectromagnet "'53 of the selector mechanisml'i is'connected toasource of supply 50 5i "througha main switch 52, contact'84, line "85, "tickselectorbuttonflgand line 86. Operationoi the tick-selector pusnbutton 44 completes the .circuitjto the electromagnet 53 drawing the arm against the action of spring49 advancing the ratchet wheel 54, together with its companion .cam 46, oneeighth.of arev'o'lution. The

turning of cam 46 from the position shown in Fig. 7 causes the contact arm '55 to 'be'moved downward :ab'out ithejpivot 56, thus fbrin'g'ing contact 58in'to connection with line 60 and'breaking 4 the-circuit between line 59 and contact 51. A second operation of the tick selector push button 44 causes a further one-eighth revolution of cam 46 and returns arm 55 to the position shown in Fig. 7.

From the mechanism heretofore described it willbe seen that the impulses produced by the audible ticks of the chronometer are first impressed on the 1 R. P. S. commutator which by reason of having half of its surface insulated eliminates one of these electrical impulses. The electrical circuit thus set up, which is for one-half second duration, is carried to the selector mechanism which utilizes this circuit should this impulse be the one desired. However, should the passage of the second hand across the scale indications occur during the duration of the alternate half second, the tick selector mechanism is brought into operation and the circuits established through the rotating commutator switched to produce the electrical impulse during the other half second period.

After selecting the proper audible signal from the speaker to coincide with the passage of the seconds hand across the scale indication the time comparator hand H is brought into coincidence with the second hand of the chronometer to be tested, by picking up the count of the chronometer seconds hand which is done by merely counting in unison with the seconds hand of the chronometer, counting each second by number as 25, 26, 27, 28 and continuing this count in unison with theaudi-ble ticks from the speaker, seconds indicating hand H is brought into close coincidence with the proper count. This would be close enough for an instrument tobe timed to within one second or to within a half second but it is desirable to time a chronometer to within one onehundredth of a second and it is necessary that accurate indication means be used to indicate exact coincidence between the indicator hand II and the seconds hand of the chronometer.

By means of the hand disc 2 the indicator hand II is brought into synchronism with the seconds hand of the chronometer and the difference in time between the chronometer and the 0 reading of the time comparator is read on the indicator scale l8.

The exact coincidence of the time comparator and the seconds hand of the chronometer is accomplished by means of a toothed wheel 29 and contacts 30, 3|, and 32. Referring more specifically to Fig. '7 a different series of numbers is applied from those shown on Fig. 1, the motor 81 being the same motor as #i in Fig. 1, said motor driving the toothed wheel 13 so that two consecutive teeth pass a given point every second. The

toothed wheel 13 shown in Fig. '7 is drawn with eight teeth to clearly show the phase position of the contacts. Actually twenty teeth are used in the preferred form of this invention. Spring arms M, 15, and 76 are so arranged about the toothed wheel 13 (#29 of Fig. 1) that within one half second, or the are represented by one of the tooth projections, all three spring arms are con- Glow lamps 89, ill and 82 are operated from the output ofthe amplifying unit 4| and blink 6 in unison with the one-half seconds ticks of the chronometer when contacts l6'i9, la-l8 or '14Tl respectively are closed during the occurrence of said one-half seconds ticks. Exact coincidence of the indicator hand II with the audible ticks of the chronometer 43 is indicated by blinking of the glow tube 8| through the circuits 88, 1B. The spring arms M and 16 are forconvenience of the operator to operate glow tubes 82 and respectively to indicate to said operator that the toothed wheel 13 is slightly retarded or advanced from its position for exact coincidence.

Referring to Fig. 2 the indicator hand I I having been manually brought into exact coincidence with the hand of the chronometer 40, the amount by which the hand II has been advanced or retarded from standard time is indicated on the scale '22 and read at the index line 98, the scale being read to one one-hundredths of a second.

The extent or duration of the contact caused by the toothed wheel is such that duration of contacts 'MTl and 75-78 overlap making glow tubes 82 and Bi both lit over a short range of adjustment of the hand wheel 2. This is true when the seconds hand H is slightly advanced in relation to the seconds hand of the chronometer and a fine adjustment of the wheel 2 eliminates the blinking of the glow lamp 82 and indicates exact coincidence between the hand Ii and the seconds hand of the chronometer to be tested; This overlapping of duration of contact is equally true between contacts 'l6i9 and contacts IS-i8 and shows a position at which the seconds indicating hand H is slightly retarded in relation to the seconds hand of the chronometer.

The operation of the device has been partially described along with the description of the parts, but to completely clarify, the microphone M is placed on the chronometer and the; sounds carried to the amplifying unit and to the transformer. From the primary of the transformer the impulses created by the sounds are directed to the glow tubes 80, 8! and 82 and through the secondary of the transformer to the commutator 66 which eliminates one of the half seconds ticks.

The alternate half second ticks which remain are made audible through the speaker 43 and the operator synchronizes this tick with the passage of the seconds hand of the chronometer across the scale indications of the seconds reading scale of the chronometer dial. This selection is accomplished through the tick selector push button 44 and the ratchet relay which has been heretofore described.

The operator now being assured that the audible tick to which he is listening corresponds to the passage of the seconds hand of the chronometer across the scale indications he brings the seconds indicating hand H of the comparator into coincidence with the seconds hand of the chronometer, first by picking up the count through glancing at the chronometer seconds hand and then counting in unison with the audible ticks he brings the seconds indicating hand ll of the comparator into apparent coincidence with the audible sounds emanating from the speaker, and the count. Exact synchronism between the seconds indicating hand H and the seconds hand of the chronometer is determined through the mechanical and electrical means heretofore described which operates the glow tubes 80, 8| and 82. Exact coincidence between the hand II and the seconds hand of the chronometer having been established, the amount by which the seconds indicating hand II has been advanced or retarded by revolving the dial wheel 2 is indicated on the scale 22, which scale is calibrated to give this time difference in hundredths of seconds.

Actually chronorneters may be timed by this apparatus in from five to ten seconds which makes it possible not only to time a vast quantity by the use of a single piece of apparatus but also by maintaining a strict schedule allows the same chronometer to be timed at practically the same time every 24 hours.

To initially start the comparator (Fig. 7) the main switch 52, a double pole single throw switch is closed, connecting the city line A. C. with'the amplifying unit iI and with the electromagnet 53. It also connects through its other pole a standard A. C. line of exactly 60 cycles with a pivoted arm and one side of a push button switch 62. Operation of the push button switch energizes the electromagnet 63 closing the arm GI and the contact 64 which maintains operation of the electromagnet 63 to keep the comparator in operation. The electromagnet E3 is used to maintain the circuit because should any outside interrupticn in the flow of current in the standard frequency line occur, the connection between the arm GI and the contact 64 would be broken and it would again be necessary to operate the push button 62 to start the apparatus. This relay mechanism prevents the apparatus from continuing to operate after momentary failure of the standard frequency current to warn the operator of said current failure.

Referring to Fig. 3 a device similar to that which has been described is shown for accurately comparing timepieces to one-fifth of a second. A base illl supports a synchronous motor H32 which operates from a source of standard frequency current turning the hand 383 which indicates seconds on the dial I64. Similar to the comparator heretofore described a hand wheel I05 revolves the motor I02 to advance or retard the hand 83 from the correct time. An index line carried by member I used in conjunction scale I I2 indicates the amount of advancement or retardation necessary to bring the hand I03 into coincidence with the hand of a timepiece to be tested.

As it is almost impossible for the human eye to synchronize separate hands on separate dials merely by watching first one hand and then the other, an arrangement is provided whereby the timepiece to be tested is first synchronized with a flashing light and this flashing light used in the final adjustment of the hand Hi3. This flashing light is used as a signal and it is to be understood that any signalling means may be used such as a speaker or other means. An apparatus for operating the flashing light consists of a synchronous motor I91 revolving ten times per minute and having a six prong star wheel I68 which closes a contact H39 once every second. By closely observing the passage of the hand of the timepiece across the second divisional lines of the seconds indicating scale of said timepiece, the flasher light may be brought into exact coincidence with this passage of the hand across the indicating marks by turning the hand wheel Hi1, thus either retarding or advancing the occurrence of the indicating flashes. The hand 93 is then brought into close coincidence with the hand of the timepiece to be tested by picking up the seconds count through awareness of the light flashes, the final accurate adjustment being made by observing the passage of the hand I63 across the indicating lines of its scale with the flashing of light III, thus making perfectly sure that the timepiece to be tested is in exact synchronism with the hand 503 of the comparator, the difference between the timepiece to be tested and the correct time being read on the scale H2 or the hand wheel I05. It is, of course, understood that previous to the test a zero setting is made with the hand I03 being set exactly on standard time and the zero point of the scale H2 in coincidence with the index N36. For convenience in making this setting the index I86 is made adjustable through set screw H3 to compensate for small errors in starting the synchronous motor at the proper instant.

Referring to Fig. 5 the comparator is mounted on a base I3I3 having a dial I3I With hands I32 and I33. This comparator is designed to check watches to within one second and has the usual synchronous motor I34 mounted on a hand wheel I35 and driving through suitable gearing the hands I32 and I33 of the indicating dial I3I. The hand wheel I35 has a spiral scale reading E33 which is read through an opening I37 in a sliding panel I38, the opening being only wide enough to permit the reading of one line of figures at once.

Revolution of the indicating hand wheel I35 turns gear Hi3 and gear segment I 34. Rotation of gear 543 is transmitted to pinion I42 through the connecting shaft and from pinion I42 to gear MI to pinion I l), gear I39 and hand I33. The partial revolution of the gear segment I causes the operating arm I45 to slide in the guide I46 and move the panel I38 upward or downward. The sliding movement of this operating arm I45 is caused by the pin Ml engaging the groove MB of the gear segment Hi l, the groove being spirally arranged in the gear segment to move the operatingarm M5 vertically. This permits the scale indications 36 to be read for more than one revolution of the hand wheel I35.

The operation of the comparator is similar to that of the ones previously described, the hands of the timepiece to be compared being synchronized with the minute hand I33 and seconds hand I32 by turning the hand wheel I35, the comparator having been first set to correct time with the scale I36 reading 0. This synchronizing of the indicator hand 532 by turning the hand wheel I35 will give a direct reading on the scale I36 of the difference in time of minutes and seconds between the timepiece to be compared and the correct time.

What I claim is:

l. A time comparator for comparing the audible ticks of a chronometer with standard time comprising a seconds hand synchronized with standard time, means for advancing or retarding said seconds hand from standard time, means indicating the amount of said advancement or retardation, a microphone for amplifying the ticks of said chronometer, an electrical circuit controlled by said microphone, a visible signal means synchronized with said seconds hand, a switch operated by said synchronized signal means, a circuit controlled by the ticks of said chronometer connected to said switch whereby the simultaneous closing of the switch by said synchronized means with a tick of said chronometer will operate said visible signal.

2. A time comparator for comparing the audible ticks of a chronometer, a source of standard frequency comprising 9, seconds hand synchronized with standard time, means for advancing or retarding said seconds hand from standard time, means indicating the amount of said advancement or retardation, a microphone for amplifying the ticks of said chronometer, an electric circuit controlled by said microphone, three visible signals in said electric circuit, a star wheel rotating with said seconds hand, three separate switches actuated by the rotation of said star wheel, said switches being in said electric circuit and adapted to control said visible signals respectively, whereby simultaneous closing of one of said switches with the tick of the chronometer indicates exact coincidence of said seconds hand with said chronometer tick and operation of either of the other signals indicates that said seconds hand is advanced or retarded from the point of coincidence.

3. A time comparator for comparing the audible ticks of a chronometer a source of standard frequency comprising a seconds hand synchronized with standard time, said seconds hand being operated by synchronous motor, means for revolving the motor either forward or backward to advance or retard the seconds hand from standard time, a dial turning with said motor to indicate the amount of such revolution and to indicate the seconds and portions of seconds advanced or retarded from standard time, a microphone amplifying the ticks of said chronometer, an electric circuit controlled by said microphone, a visible signal in said electric circuit, a switch for closing said circuit to operate said signal, means synchronous with saidseconds hand for mechanically closing said switch, whereby simultaneous closing of the switch with the tick of the chronometer will operate said visible signal.

WILLIAM OGLE BENNETT, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,066,349 Hellweg et a1 Jan. 5, 1937 2,092,039 Young Sept. 7, 1937 2,120,140 Agnew June '7, 1938 2,188,059 Norrman Jan. 23, 1940 2,317,202 Kohlhagen Apr. 20, 1943 2,322,861 Luckey June 29, 1943 2,352,906 Lyons July 4, 1944 

